Apparatus for making glass



Dec. i4, 1926. lgw

- H. F., H11-NER APPARATUS FR MAKING GLASS Original Filed August 2'0 1925 3 Sheeus-Sheet 1 Il I Dec. 1&4, 1926. Ll?? H. F. HITNER APPARATUS FOR MAKING GLASS Oriana Filed August 2O 19.25 3 Sheets-Sheet 2 j Q 2 N $1 UNVENTOR H. F. HITNER APPARATUS FOR MAKING GLASS Original Filed August 2O 1925 3 Sheets-Sheet 5 :NVENTQR Patented Dec. 14, 1926.

.UNITED STATESl PATENT OFFICE.

HARRY F. HITNER, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO PITTSBURGH PLATE GLASS COMPANY, A CORPORATION OF PENNSYLVANIA.

APPARATUS FOR MAKING GLASS.

Application illed August 20, 1925, Serial No. 51,325. Renewed April 17, 1926.

The invention relates to an apparatus for making glass by the use of electricity as a melting and fining agent.- The apparatus'constitutes a modification of that shown in my copending application, Serial No.

51,324, of even date herewith; such application disclosingr the use of plate electrodes set into the sides of the tank and designed to be used with single phase current` while the apparatus of the present application discloses the use of electrodes in the form of pools of molten metal inthe bottom of the melting tank arranged so as to be `used with three phase current. The feature of ar- 5 ranging the electrodes in pairs in spaced relation longitudinally of the tank and adapted to secure a flow of current through the glass longitudinally of the tank, and also transversely, isA common to bothapplications, the broad claims to this feature being presented in said copending` application. As in such other application, the gases above the glass are withdrawn at the rear end of the tank, so as to preliminarily vheat the incoming batch. The objects'of the invention are to provide for heating the glass thoroughly and uniformly in va economical way. and to prevent any reaction between the electrodes and the glass such as o would cause a discoloration of the glass or injury to its quality due to such reaction. In its preferred form'` the invention contemplates the use of three phase current in conjunction `with two transformers designed so as to give different voltages, the higher volt-v age being applied to the reduction of the batch in the rear section of the tank, to which it is better adapted than the lower voltage. while the lower voltage is applied 0 to the finiug` of the glass in the tank section forward of such rear section. One embodiment of the invention is illustrated in the accompanying drawings wherein: i Figure 1 is a vertical section through the apparatus on the line I-I of Fig. 2. Fig.

2 is a horizontal section on the line IL-II of Fig. 1. Fia'. 3 is a transverse section on the line III-III of Fig. 1. And Fig. 4 is a wiring diagram.

Referring to the drawings. 1. 2 are the side walls of an elongated melting tank; 3 and 4 are the rear and forward end walls re.- spectively; and 5 is the arch or roof of the tank. Batch is supplied to the rear end of the tank through the chute 6 and the tinished glass is withdrawn continuously from the' forward end of the tank through the slot 7 in the front wall 4, such wall being preferably made vertically adjustable or removable by means of chains 8 connected to a suitable overhead handling device. i

The glass flowing through the slot 7 passes between' the sizing rolls 9 and 10 in a continuous ribbon 11, the sizing rolls being water cooled and driven from the shaft 12 (Fig. 2) through the intermediary, ofthe tumbler shafts 18 and suitable reducing gearing in the casings 14 and 15. The ribbon is lreceived from an apron provided with fluid cooled rolls 16 and passes from this apron into a leer 17, which is preferably of the roller type, and is of such length that the glass is suitably annealed and cooled before reaching the far end of the leer where it is cutinto sheets. Provision is made for cutting off the How of glass from the outlet slot 7 in the form of a pair of lgates or shear cakes 18 and 19, the gate 18 being water cooled, and the gate 19 being of refractory material. These gates are supported by the chains 2O and 21 extending upward to a suitable handling apparatus, such as an overhead crane. v

The hot gases which accumulate above the surface of the glass in the tank are carried out through the chute 6 and throughv the passageway 22 leading to a' stack and provided with a suitable regulating damper 23. The passageway 22 is arranged along one side of the batch hopper 24, and this batch hopper is provided at its lower end with a gate-25 secured to a. segmental rack 26 which is operated by the pinion 27. This pinion is carried by the shaft upon which the wheel 28 is mounted and this wheel may be turned from/,the depending endless chain 29. The hopper 24 is su plied from a bin 30 having a chute 31 discharging to the hopper.

Located in the bottom wall of the tank along the sides thereof are the pairs of electrodes A-B, C--D, an-d E-F, such electrodes being in the form of pools ofmolten metal, heavier than glass, such as lead, antimony or copper, the metal selected being one which will not react with the glass at the temperatures at which the apparatus is operated. Of the three metals i specified, the antimony is'preferred, as u: on

oxidation, it does not form a corrosive ux and attack the furnace lining, as is the ease with both the lead and the copper. Further, antimony oxide does not color the glass Aand has been found to be a desirable ingredient in the batch, because of its effect in ining the glass. On the other hand, lead oxide tends to give the glass a yellow tinge, while Y copper oxide gives it a blue tinge. -The sur lfaces of these pools of metal are preferably located slightlybelow the `level of the bottom of the tank, and current is suppliedto the pools by means of lead-in terminals A. B', C', D', E', and F' whichextend into the molten metal constituting the pools.

The current employed is alternating and three phase from the leads G, I-I and I. K

is the secondary of a high voltage transformer and L `is the secondary of another transformerV for giving lower voltage, Leading from the branches of the transformer windings are the sets of connections M, N, O, P, Q and R which connect with the lead-inv terminals A', B', C. D', E', and

and D, between A and C and between A and B. Similarly, a iow may occur between B and D and between B and C. In addition to this, a similar series of paths of iow may be secured between the electrodes C, .D, E and F, as for instance, between C and E and C and F, or between D and F and D vand E.

The melting of the batch is accomplished l by the high voltage current between the electrodes A` B, C and D which is better adapted to this work than the lower voltage, while the fining action is secured by the flow of current between the electrodes C, D`

E and F. f The spacing of the electrodes andv the current supplied may be varied to suit condltions and requirements. A very close regulation of temperature may be secured l and a product of a high qual-ity produced.

The glass is skimmed in the usual way by means of the sets of floatens 532-32, and

33-33. A very considerable degree of economy 1s secured because the energy of the current 1s utilized and the radiation losses from`tl1ey furnace arev relatively slight as compared with a gas heated furnace. Furthermore, with this type of furnace, the

i heated lgases above the glass may be utilized lfor heating the incoming batch, an economy `not possible with gas heated furnaces. The

process also involves a saving in alkali, as I the vaporized alkali, ordinarily lost' and amounting to something like 15 per cent, which is condensed and returned `with the incoming batch.`

What I claim is:

g1'. In combination in apparatus for making glass, a. melting tank arranged to receive batch at one endand deliver molten glass at the other end, a plurality of electrodes in the bottom of the tank along each side thereof in spaced relation and` each comprising a pool of molten metal, and means for supplying current to the electrodes so as to cause the -ilow thereof to pass through the glass longitudinally of the tank.

2, In combination in apparatus for making glass, a melting tank arranged to receive batch at one end and deliver molten glass at the other end, a plurality of electrodes in the bottom of the tank along each side lthereof in spaced relation and each comprising a pool of molten metal, and means for supplyingcurrent to the electrodes so as to cause the How thereof to pass through the glass longitudinally of the tank and also transversely thereof.

3. In combination in apparatus for making glass, a melting tank arranged to receive batch' at one end and deliver molten glass at the other end. a plurality of electrodes in the bottom of the tank along each side thereof in spaced relation and each comprisint! a pool of molten metal. and means for supplying current to the electrodes so as to cause the liow thereof to pass through the glass diagonally of the tank in a plurality of paths. i

4. In combination in apparatus for making glass, a melting tank arranged lto receive batch at one end and deliver molten glass at theother end. a plurality of electrodes in the bottom of the tank, along each side thereof in spaced relation. and each comprising a pool of molten metal. and means for supplying current to the electrodes so as to cause the flow thereof to pass through the glass longitudinally of the tank and also transversely and diagonally thereof.

5. In combination in apparatus for making glass, a melting tank arranged to receive batch at one end and deliver molten .glass at the other end. three electrodes in the bottomof the tank in spaced'relation longitudinally thereof, and each comprising a pool of moltenmetal and means for supplying current to theelectrodes so as to cause 6. In combination in apparatus for mak# mg glass, a melting tank arranged to receive each side thereof, and also so as to cause the How of current transversely of the tank between each pair of end electrodes.y

7. In combination in apparatus for making glass, a melting tank arrangedto receive batch at one end and deliver molten glass at the other end, three electrodes in the bottom of the tank on each side thereoi in spaced relation longitudinally thereof, and comprising a pool of molten metal, and means for supplying current to the electrodes, so as to canse a iow thereof longi# tudinally lof the tank between the middle electrodes and the end electrodes lying on each side thereof, and also so as to cause a llow of current diagonally of the tank between each of the middle electrodes and the end electrodes on the sides of the tank opposite therefrom.

8. In combination in apparatus for making glass, a melting tank arranged to receive batch at one end and deliver molten glass at the other end, three electrodes in the bottom of the tank on each'side thereof in spaced relation longitudinally thereof, and each comprising a pool of molten metal,

vand means for supplying current to the electrodes, so as to cause a flow thereof diagonaliy of the tank between each of the middle electrodes andthe end electrodes on the.

sides of the tank opposite therefrom.

9. In combination in apparatus for makin glass, a melting tank arranged to receive batch at one end and deliver molten lass at the other end, threeelectrodes in the ottom of the tank in spaced relation longi tudinally thereof, and each comprising a pool of molten metal and means for supply ing current to the electrodes s o as to cause a flow thereof longitudinally of the tank between the middle'electrode and the'electrodelying on one side thereof of one voltage, and another flow longitudinally of the tank between the middle electrode and the elecfv ,4

trode -On the otherside thereof of a voltage different from the first voltage.A

10. In combination in apparatus for making glass, a melting tank arranged to receive batch at one end and deliver molten glass at the other end, three electrodes in the bottom of the tank in spaced relation longitudinally thereof, and each comprising a pool of molten metal and means for supplying current to the electrodes so as to cause a flow thereof longitudinally of the tank between the middle electrode and the electrode lying on one side thereof of one voltage, and another flow longitudinally of the tank between the middle electrode land the electrode on the other side thereof of a voltage different from the first voltage, the higher voltage being applied on the side of the middle electrode toward the rear end of the tank. v

11. In combination in apparatus for making glass, a melting tank arranged to receive batch at one end and deliver molten the bottom of the tank on each side thereof in spaced relation longitudinally thereof, and each comprising a pool of molten metal, and means for supplying current to the electrodes, so as. to cause a flow thereof long!- tudinally of the tank between the middle electrodes. and the end electrodes lying on each side thereof, and also so as to cause the flow of current transversely of the tank between each pair of end electrodes, the voltage of the current flowing between the middle electrodes and the end electrodes to the rear thereof being higher than the voltage of the current between such middle electrodes and the end electrodes forward thereo glass at the other end, three electrodes in 12. In combination in apparatus for makl ing glass, a tank or container adapted to carry a body of molten glass, and means trodes, so as to cause the flow thereof to pass through the glass In testimonyy whereof, I have hereunto subscribed my name this 18th day of July, 

